Expression and Regulation of a Silent Operon, hyf, Coding for Hydrogenase 4 Isoenzyme in Escherichia coli
2004 ◽
Vol 186
(2)
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pp. 580-587
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ABSTRACT On the basis of hyf-lacZ fusion studies, the hyf operon of Escherichia coli, noted for encoding the fourth hydrogenase isoenzyme (HYD4), is not expressed at a significant level in a wild-type strain. However, mutant FhlA proteins (constitutive activators of the hyc-encoded hydrogenase 3 isoenzyme) activated hyf-lacZ. HyfR, an FhlA homolog encoded by the hyfR gene present at the end of the hyf operon, also activated transcription of hyf-lacZ but did so only when hyfR was expressed from a heterologous promoter. The HYD4 isoenzyme did not substitute for HYD3 in H2 production. Optimum expression of hyf-lacZ required the presence of cyclic AMP receptor protein-cyclic AMP complex and anaerobic conditions when HyfR was the activator.
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1998 ◽
Vol 180
(23)
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pp. 6117-6125
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1986 ◽
Vol 261
(24)
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pp. 11315-11319
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2001 ◽
Vol 183
(17)
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pp. 5187-5197
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1988 ◽
Vol 263
(17)
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pp. 8072-8077
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2002 ◽
Vol 68
(8)
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pp. 4107-4110
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